Peope have trust in gold. Because gold is using since hundred of years as something very valuable and rare. But when you think about it, its useless. You can use small amount of it for electronic parts, and thats it. Its just the trust of centurys why the people think gold is valuable. But gold is the biggest bubble in the history mankind. Nobody knows how much really exist. There are so many banks who owns fake gold. So if you think about it, its crazy that gold can be so much worth.
Exactly, what is important is perceived value. EUR and USD do not have any internal value at all but they are still considered as a secure way to keep your money. Nowadays perceived value of BTC is still low. This fact scares off ordinary people from investing in and using it. If BTC will be widely known and be used for everyday shopping for example it will be considered as something valuable and trusted.